If they see more than 10 taps, police assume the driver is sending a text message, according to Lisiecki, who heads the North Huntingdon department.

It's unscientific, but it's just one method police have found to determine if a driver is violating the state's 8-month-old ban on texting while driving, a law many officers say is ineffective and nearly impossible to enforce.

"We're still seeing the same distracted drivers out there that are texting," Lisiecki said. "All the driver has to say is, 'I was punching in a phone number.' It's tough to enforce."

Citations issued statewide stand at 901 to date, an average of about 112 a month since the law went into effect on March 8, according to records from the Administrative Office of Pennsylvania Courts and the Philadelphia Police Department, which compiles its own statistics.

But even when police believe they have grounds to issue a citation, district judges say they too often have to dismiss the cases for lack of evidence.

Ed Spreha, an attorney who leads seminars for district judges about the state's Motor Vehicle Code, said the texting law is definitely "beatable" although many motorists don't fight their tickets because they're relatively inexpensive - $50 per violation - and carry no points against their driving records.

Frequently, those cited tell judges they were dialing a phone number or talking on their cell phones, both permitted under the law, which also allows drivers to use navigation devices and other electronic gadgets, Lisiecki said.

Although it's difficult to prosecute distracted drivers, it's easy to spot their textbook behaviors, according to state police spokesman Steve Limani of the Greensburg barracks.

"There's no reason to be looking down in your lap when you're driving," Limani said, referring to the position drivers typically assume when they're trying to hide their texting from police.

Limani said texting drivers often weave in and out of traffic, drive at inconsistent speeds and stop longer at intersections and stop signs.

But Whitehall District Judge Dave Barton said that even when police are sure they've nabbed a violator, the law often doesn't stand up in court, a fact he believes deters some officers from citing drivers.

"I'm sure they don't want to write citations if they think they're going to have a hard time enforcing it," he said.

To prove a violation, police can seek search warrants to seize and examine a cell phone, said Westmoreland County Assistant District Attorney Peter Flanigan. But most police say that takes too much time and trouble for a traffic citation.

However, Flanigan said drivers should expect police to seek search warrants for iron-clad proof in some situations.

"It can be anticipated that when the violation occurs in connection with a more serious offense, a search warrant may be utilized to seize and search the device," said Flanigan, adding that cell phone tower records can be used to pinpoint usage.

Brookline District Judge James Motznik said the simple solution is to ban all hand-held devices.

"It is difficult for an officer to determine if someone is texting or making a phone call, but an officer shouldn't have to," Motznik said.

In eight months, Brentwood and Baldwin District Judge John Bova has heard only one texting-while-driving case in his busy courtroom. He said he had no choice but to dismiss it because of insufficient evidence.

"I would personally like to see all cell phones not being used when you're driving a motor vehicle," Bova said. "Having hands on the wheel is just better. It will cause less accidents, without question."

About 3,000 people were killed in crashes involving distracted drivers in 2010, according to the National Highway Traffic Safety Administration.

About 82 percent of adults own a cell phone, and 27 percent have said they used theirs to send or read a text message while driving. That compares to about 26 percent of teens who admitted to texting while driving, according to the Pew Research Center.

Those drivers are 23 times more likely to be involved in a crash than a non-distracted driver, according to the National Highway Traffic Safety Administration.

But some say enacting a ban on all handheld devices could be a steep hill to climb. In Pennsylvania and other states, lawmakers have engaged in bitter partisan battles over the issue.

To date, 10 states and the District of Columbia have banned handheld devices, while 39 have banned texting while driving.

State Rep. Joe Markosek, D-Monroeville, said the law "was certainly a watered-down version" of what was originally introduced, but he said it was a "start."

"Ï don't think we finished the job," said Markosek, who hopes to introduce a bill during the next session to ban all handheld devices but permit BlueTooth or other hands-free technology.

Steve Miskin, spokesman for state Rep. Mike Turzai, R-Bradford Woods, blamed the heated debate preceding passage of the law on legislators attaching unrelated measures to the distracted-driving bill.

"You had everything in one omnibus bill, and it was never able to pass," Miskin said. "So we broke it up."

Miskin said many lawmakers want to "see how it goes" with the texting law before considering extending the ban.

One former lawmaker who was front and center during the debate over the texting ban said he thinks it's doubtful that all handheld devices will be prohibited.

Former state Rep. Josh Shapiro said House leaders will do everything possible to block such a move.

"We compromised on a ban of texting while driving, and it does what we wanted -- making it a primary offense," Shapiro said. Because it is a primary offense, police can stop drivers solely for suspicion of texting while driving.